A/C is blowing hot and cold

racerdad2007
Posts: 1
Joined: Fri May 17, 2013 10:53 pm

A/C is blowing hot and cold

Unread post by racerdad2007 » Fri May 17, 2013 11:04 pm

I have a 2000 Chev. S-10 Blazer 4.3 that just had lower intake gaskets replaced and now, when the a/c is turned on, air goes hot to cold to hot, not warm, repeatedly. It has climate control and the compressor is staying on, not cycling. A/C was working perfectly before gaskets were replaced. HELP PLEASE!!!!!

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ProTech
Posts: 651
Joined: Wed Oct 17, 2012 10:08 am

Re: A/C is blowing hot and cold

Unread post by ProTech » Sat May 18, 2013 12:39 pm

You might want to look and make sure everything is plugged in, especially on the back of the compressor. It would have had to been moved during the intake job so probably has something to do with that. There are two connectors on the back, one to power it up and another for the pressure sensor (if equipped). Or possibly one of the harnesses got pinched. If the A/C is running constantly, you're probably freezing up the evaporator core which would then blow hot air until it defrosted enough to blow cold again, over and over. Give a check over the area that the work was done, you'll probably find the problem in that area.
GM Dealer Technician For 18+ Years
In the automotive industry for 20+

EMEDIO
Posts: 1
Joined: Tue Apr 11, 2017 3:33 pm

Diagnosis

Unread post by EMEDIO » Tue Apr 11, 2017 3:42 pm

I have a 2004 blazer ls sometime I get good heat other times it's warm or cold air . Normal operating temp has always been just below 210 degrees now it increases to just over 210 then after a short while it goes back to normal

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carriedi
Posts: 2573
Joined: Wed Apr 10, 2013 12:42 pm

Re: Diagnosis

Unread post by carriedi » Tue Apr 11, 2017 9:05 pm

first thing to do is check your coolant level. If the coolant gets low in the system you may not get flow through the heater core.

next time the heat is not coming out hot, check the two hoses that go to the heater core. see if one is hot and one is not so hot. You could have a heater core that is starting to plug up.
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